Top definition
A type of shit that leaves you speculating whether you actually had one because:

A) It went down the U-Bend so went you look you can't see it.

B) The tissue is clean when you wipe

Both these together result in a double mystery and leave yourself questioning your own sanity.
Person 1: I just took a double mystery.
Person 2: How'd you know, you could have just thought you had a shit?
by OndaLash July 18, 2011
Get the mug
Get a Double Mystery mug for your coworker Georges.